This is my code and it perfectly returns number of days and months between two dates. i want to validate this like the difference between two dates should be exactly one year.like if u select july 29 2013 as start date and july 30 2014 as end date it should not be allowed to execute more.please help thanks in advance.
NSString *sta = txtStartdate.text; // This is the start date
NSString *en = txtEnddate.text; //this is end date
NSDateFormatter *f = [[NSDateFormatter alloc] init];
[f setDateFormat:#"dd/MM/yyyy"];
NSDate *startDat = [f dateFromString:sta];
NSDate *endDat = [f dateFromString:en];
[f release];
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit | NSYearCalendarUnit ;
NSDateComponents *components = [gregorian components:unitFlags
fromDate:startDat
toDate:endDat options:0];
NSInteger months = [components month];
NSInteger days = [components day];
NSInteger years = [components year];
NSLog(#"Number of months %d",months);
NSLog(#"Number of days %d",days);
NSLog(#"Number of years %d",years);
[gregorian release];
if(years < 1 )// This code works fine...i've edited it.. #wain helped
{
//
}
Add NSYearCalendarUnit to unitFlags, then when you have obtained the components you can request the year. This will deal with leap years better than you trying to count months and days or calculate the end date (unless you use the components to add a single year to the date to get the end date).
Related
I am using this method to get the current week first and last days:
NSDate *weekDate = [NSDate date];
NSCalendar *myCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *currentComps = [myCalendar components:( NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekOfYearCalendarUnit | NSWeekdayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit) fromDate:weekDate];
int ff = currentComps.weekOfYear;
NSLog(#"1 %d", ff);
[currentComps setWeekday:1]; // 1: sunday
NSDate *firstDayOfTheWeek = [myCalendar dateFromComponents:currentComps];
[currentComps setWeekday:7]; // 7: saturday
NSDate *lastDayOfTheWeek = [myCalendar dateFromComponents:currentComps];
NSDateFormatter *myDateFormatter = [[NSDateFormatter alloc] init];
myDateFormatter.dateFormat = #"dd/MM/yyyy";
NSString *firstStr = [myDateFormatter stringFromDate:firstDayOfTheWeek];
NSString *secondStr = [myDateFormatter stringFromDate:lastDayOfTheWeek];
NSLog(#"first - %# \nlast - %#", firstStr, secondStr);
And i want to know what i should change in this to get the next week first and last day and two weeks from now to?
To get the next week, add 7 days to firstDayOfTheWeek and then lastDayOfTheWeek.
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:7];
NSDate *firstDayOfNextWeek = [myCalendar dateByAddingComponents:comps toDate:firstDayOfTheWeek options:0];
This code assumes a 7-day week. Ideally you would replace this assumption with code that gets the actual length of the week.
Side Note: Your code assume the week starts on Sunday. Many locales start their week on others days such as Monday. Change:
[currentComps setWeekday:1];
to:
[currentComps setWeekday:[myCalendar firstWeekday]];
I would then change your calculation of lastDayOfTheWeek to simply add 6 days to firstDayOfWeek.
Use Below code which returns index of current current weekly days. For example if its today is saturday than it will give you 7 means last day of week.
-(int)currentdayweeklynumber{
NSDate *CurrentDate = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd"];// you can use your format.
//Week Start Date
NSCalendar *gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:CurrentDate];
int dayofweek = [[[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:CurrentDate] weekday];
NSLog(#" dayofweek=%d",dayofweek);
return dayofweek;
}
Using this number you add or subtract to get first or last of week. You can also use this get next week start and end date by just simple calculation.
I am using the following code to find from current date+time to 30 days future. It works fine. But, i want now the end date should be 60 days, not 30 days. How can i change the below code to get upto 60 days? I tried changing end date to [currentDateComponents month]+1, but its not working. Any help please?
NSDate *date = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *currentDateComponents = [gregorian components:( NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSWeekCalendarUnit) fromDate:date];
NSLog(#"- current components year = %d , month = %d , week = % d, weekday = %d", [currentDateComponents year], [currentDateComponents month], [currentDateComponents week], [currentDateComponents weekday]);
NSArray* calendars = [[CalCalendarStore defaultCalendarStore] calendars];
NSLog(#"calendars.count: %ld", [calendars count]);
debug(#"LogMsg:%# Date:%#", #"Start looking for new events for pushing iCal to OfferSlot", [NSDate date]);
// 30 days any new or modified calendar (iCal) events will be pushed here to OfferSlot
NSInteger year = [[NSCalendarDate date]yearOfCommonEra];
NSDate *startdate = [NSCalendarDate dateWithYear:year month:[currentDateComponents month] day:1 hour:0 minute:0 second:0 timeZone:nil];
NSDate *enddate = [NSCalendarDate dateWithYear:year month:[currentDateComponents month] day:31 hour:23 minute:59 second:59 timeZone:nil];
Your code does not always do what you describe in the text. It creates two dates, one at the beginning of the current month, one at the end of the month (if the month has 31 days, if it has less than 31 days your endDate will be in the next month). If you run the code on the 1st of each month it will create a NSDate that is 30 days in the future, but only on the 1st of each month.
if you really want to get the NSDate that is 60 days from now use this code:
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *sixtyDaysOffset = [[NSDateComponents alloc] init];
sixtyDaysOffset.day = 60;
NSDate *sixtyDaysFromNow = [calendar dateByAddingComponents:sixtyDaysOffset toDate:[NSDate date] options:0];
I'm writing a GTD app for the iPhone. For the due tasks, I want to display something like "Due tomorrow" or "Due yesterday" or "Due July 18th". Obviously, I need to display "Tomorrow" even if the task is less than 24 hours away (e.g. the user checks at 11pm on Saturday and sees there's a task on Sunday at 8am). So, I wrote a method to get the number of days in between two dates. Here's the code...
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd-HH-mm"];
NSDate *nowDate = [dateFormatter dateFromString:#"2010-01-01-15-00"];
NSDate *dueDate = [dateFormatter dateFromString:#"2010-01-02-14-00"];
NSLog(#"NSDate *nowDate = %#", nowDate);
NSLog(#"NSDate *dueDate = %#", dueDate);
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *differenceComponents = [calendar components:(NSDayCalendarUnit)
fromDate:nowDate
toDate:dueDate
options:0];
NSLog(#"Days between dates: %d", [differenceComponents day]);
... and here's the output:
NSDate *nowDate = 2010-01-01 15:00:00 -0700
NSDate *dueDate = 2010-01-02 14:00:00 -0700
Days between dates: 0
As you can see, the method returns incorrect results. It should have returned 1 as the number of days between the two days. What am I doing wrong here?
EDIT: I wrote another method. I haven't done extensive unit tests, but so far it seems to work:
+ (NSInteger)daysFromDate:(NSDate *)fromDate inTimeZone:(NSTimeZone *)fromTimeZone untilDate:(NSDate *)toDate inTimeZone:(NSTimeZone *)toTimeZone {
NSCalendar *calendar = [NSCalendar currentCalendar];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
[calendar setTimeZone:fromTimeZone];
NSDateComponents *fromDateComponents = [calendar components:unitFlags fromDate:fromDate];
[calendar setTimeZone:toTimeZone];
NSDateComponents *toDateComponents = [calendar components:unitFlags fromDate:toDate];
[calendar setTimeZone:[NSTimeZone defaultTimeZone]];
NSDate *adjustedFromDate = [calendar dateFromComponents:fromDateComponents];
NSDate *adjustedToDate = [calendar dateFromComponents:toDateComponents];
NSTimeInterval timeIntervalBetweenDates = [adjustedToDate timeIntervalSinceDate:adjustedFromDate];
NSInteger daysBetweenDates = (NSInteger)(timeIntervalBetweenDates / (60.0 * 60.0 * 24.0));
NSDateComponents *midnightBeforeFromDateComponents = [[NSDateComponents alloc] init];
[midnightBeforeFromDateComponents setYear:[fromDateComponents year]];
[midnightBeforeFromDateComponents setMonth:[fromDateComponents month]];
[midnightBeforeFromDateComponents setDay:[fromDateComponents day]];
NSDate *midnightBeforeFromDate = [calendar dateFromComponents:midnightBeforeFromDateComponents];
[midnightBeforeFromDateComponents release];
NSDate *midnightAfterFromDate = [[NSDate alloc] initWithTimeInterval:(60.0 * 60.0 * 24.0)
sinceDate:midnightBeforeFromDate];
NSTimeInterval timeIntervalBetweenToDateAndMidnightBeforeFromDate = [adjustedToDate timeIntervalSinceDate:midnightBeforeFromDate];
NSTimeInterval timeIntervalBetweenToDateAndMidnightAfterFromDate = [adjustedToDate timeIntervalSinceDate:midnightAfterFromDate];
if (timeIntervalBetweenToDateAndMidnightBeforeFromDate < 0.0) {
// toDate is before the midnight before fromDate
timeIntervalBetweenToDateAndMidnightBeforeFromDate -= daysBetweenDates * 60.0 * 60.0 * 24.0;
if (timeIntervalBetweenToDateAndMidnightBeforeFromDate < 0.0)
daysBetweenDates -= 1;
}
else if (timeIntervalBetweenToDateAndMidnightAfterFromDate >= 0.0) {
// toDate is after the midnight after fromDate
timeIntervalBetweenToDateAndMidnightAfterFromDate -= daysBetweenDates * 60.0 * 60.0 * 24.0;
if (timeIntervalBetweenToDateAndMidnightAfterFromDate >= 0.0)
daysBetweenDates += 1;
}
[midnightAfterFromDate release];
return daysBetweenDates;
}
From the docs for components:fromDate:toDate:options::
The result is lossy if there is not a small enough unit requested to hold the full precision of the difference.
Since the difference is less than a full day, it correctly returns a result of 0 days.
If all you care about is tomorrow or yesterday vs. a specific date, then you can save yourself a lot of work and just test whether the dates are only one calendar day apart.
To do that, compare the dates to find which is earlier and which is later (and if they compare equal, bail out with that result), then test whether 1 day after the earlier date produces a date with the same year, month, and day-of-month as the later date.
If you really do want to know exactly how many calendar days there are from one date to the other:
Send the calendar a components:fromDate: message to get the year, month, and day-of-the-month of the first date.
Same as #1, but for the second date.
If the two dates are in the same year and month, subtract one day-of-month from the other and pass to abs (see abs(3)) to take the absolute value.
If they are not in the same year and month, test whether they are in adjacent months (e.g., December 2010 to January 2011, or June 2010 to July 2010). If they are, add the number of days in the earlier date's month (which you can obtain by sending the calendar a rangeOfUnit:inUnit:forDate: message, passing NSDayCalendarUnit and NSMonthCalendarUnit, respectively) to the day-of-month of the later date, then compare that result to the earlier date's day-of-month.
For example, when comparing 2010-12-31 to 2011-01-01, you would first determine that these are in adjacent months, then add 31 (number of days in 2010-12) to 1 (day-of-month of 2011-01-01), then subtract 31 (day-of-month of 2010-12-31) from that sum. Since the difference is 1, the earlier date is one day before the later date.
When comparing 2010-12-30 to 2011-01-02, you would determine that they are in adjacent months, then add 31 (days in 2010-12) to 2 (day-of-month of 2011-01-02), then subtract 30 (day-of-month of 2010-12-30) from that sum. 33 minus 30 is 3, so these dates are three calendar days apart.
Either way, I strongly suggest writing unit tests at least for this code. I've found that date-handling code is among the most likely to have subtle bugs that only manifest, say, twice a year.
One thing you might try is using rangeOfUnit: to zero out hours, minutes and seconds from the start and end dates.
NSCalendar *calendar = [NSCalendar currentCalendar];
NSCalendarUnit range = NSDayCalendarUnit;
NSDateComponents *comps = [[NSDateComponents alloc] init];
NSDate *start = [NSDate date];
NSDate *end;
[comps setDay:1];
[calendar rangeOfUnit:range startDate:&start interval:nil forDate:start];
end = [calendar dateByAddingComponents:comps toDate:start options:0];
In this example start will be 2010-06-19 00:00:00 -0400, end will be 2010-06-20 00:00:00 -0400. I'd imagine this would work better with NSCalendar's comparison methods, although I haven't tested it myself.
I am using this piece of code, it is working very well:
- (NSInteger)daysToDate:(NSDate*)date
{
if(date == nil) {
return NSNotFound;
}
NSUInteger otherDay = [[NSCalendar currentCalendar] ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitEra forDate:date];
NSUInteger currentDay = [[NSCalendar currentCalendar] ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitEra forDate:self];
return (otherDay-currentDay);
}
Here is the function I've used in the past
its defined in a category on NSDate
- (int) daysToDate:(NSDate*) endDate
{
//dates needed to be reset to represent only yyyy-mm-dd to get correct number of days between two days.
NSDateFormatter *temp = [[NSDateFormatter alloc] init];
[temp setDateFormat:#"yyyy-MM-dd"];
NSDate *stDt = [temp dateFromString:[temp stringFromDate:self]];
NSDate *endDt = [temp dateFromString:[temp stringFromDate:endDate]];
[temp release];
unsigned int unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [gregorian components:unitFlags fromDate:stDt toDate:endDt options:0];
int days = [comps day];
[gregorian release];
return days;
}
-(NSInteger)daysBetweenTwoDates:(NSDate*)fromDateTime andDate:(NSDate*)toDateTime
{
NSDate *fromDate;
NSDate *toDate;
NSCalendar *calendar = [NSCalendar currentCalendar];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&fromDate
interval:NULL forDate:fromDateTime];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&toDate
interval:NULL forDate:toDateTime];
NSDateComponents *difference = [calendar components:NSDayCalendarUnit
fromDate:fromDate toDate:toDate options:0];
return [difference day];
}
Reference to pre-answered question at: Getting first and last days of current week
There are two answers in the above link. One of them is theoretical and the other is in a language called as PyObjC (Python-Objective C bridge language), and a quick google search confirms that PyObjC does not work with iPhone SDK.
So regarding the question, how is it possible to get the PyObjC code translated to be compatible with iPhone SDK.
Target: Supposing today (Tue.) is 19th, and Sun. was 17th (start of week) and Sat. 23rd is end of week. I want to get a string like 19/01 - 23/01 [i.e. The start of week (hypen) end of week]
If you have an NSDate, you can use the current NSCalendar to retrieve that date's NSDateComponents. Set the NSDateComponents's weekday to 1 (the first day of the week), create a copy, and set the copy's weekday to 7 (the last day of the week). Then use the NSCalendar to convert both the NSDateComponents back to their respective NSDate objects, after which you can use an NSDateFormatter to create your string representation.
This link has an example about how to get a date's weekday: https://stackoverflow.com/questions/1057349#1057405
Here's some code and it also checks an edge case where the beginning of the week starts in the prior month:
// Finds the date for the first day of the week
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
NSCalendar *calendar = [NSCalendar currentCalendar];
// Edge case where beginning of week starts in the prior month
NSDateComponents *edgeCase = [[NSDateComponents alloc] init];
[edgeCase setMonth:2];
[edgeCase setDay:1];
[edgeCase setYear:2013];
NSDate *edgeCaseDate = [calendar dateFromComponents:edgeCase];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:edgeCaseDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Edge case date is %# and beginning of that week is %#", edgeCaseDate , [calendar dateFromComponents:components]);
// Find Sunday for the given date
components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Original date is %# and beginning of week is %#", givenDate , [calendar dateFromComponents:components]);
return [calendar dateFromComponents:components];
}
Edit: Relevant code from above
- (NSDate *)firstDayOfWeekFrom:(NSDate *)givenDate {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeekOfYear:[components weekOfYear]];
return [calendar dateFromComponents:components];
}
This is what I was looking for days ago and finally found. There is a method rangeOfUnit:startDate:interval:forDate: in NSDate and do that in a simple way. You can see detail at:
Current Week Start and End Date
NSDate *weekDate = [NSDate date];
NSCalendar *myCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *currentComps = [myCalendar components:( NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekOfYearCalendarUnit | NSWeekdayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit) fromDate:weekDate];
int ff = currentComps.weekOfYear;
NSLog(#"1 %d", ff);
[currentComps setWeekday:1]; // 1: sunday
NSDate *firstDayOfTheWeek = [myCalendar dateFromComponents:currentComps];
[currentComps setWeekday:7]; // 7: saturday
NSDate *lastDayOfTheWeek = [myCalendar dateFromComponents:currentComps];
NSDateFormatter *myDateFormatter = [[NSDateFormatter alloc] init];
myDateFormatter.dateFormat = #"dd EEEE";
NSString *firstStr = [myDateFormatter stringFromDate:firstDayOfTheWeek];
NSString *secondStr = [myDateFormatter stringFromDate:lastDayOfTheWeek];
NSLog(#"first - %# \nlast - %#", firstStr, secondStr);
Does anyone know if there is a way to set the first day of the week on a NSCalendar, or is there a calendar that already has Monday as the first day of the week, instead of Sunday.
I'm currently working on an app that is based around a week's worth of work, and it needs to start on Monday, not Sunday. I can most likely do some work to work around this, but there will be a lot of corner cases. I'd prefer the platform do it for me.
Thanks in advance
Here's some the code that I'm using. it's saturday now, so what I would hope is that weekday would be 6, instead of 7. that would mean that Sunday would be 7 instead of rolling over to 0
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setFirstWeekday:0];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *todaysDate = [gregorian components:unitFlags fromDate:[NSDate date]];
int dayOfWeek = todaysDate.weekday;
Edit: This does not check the edge case where the beginning of the week starts in the prior month. Some updated code to cover this: https://stackoverflow.com/a/14688780/308315
In case anyone is still paying attention to this, you need to use
ordinalityOfUnit:inUnit:forDate:
and set firstWeekday to 2. (1 == Sunday and 7 == Saturday)
Here's the code:
NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
[gregorian setFirstWeekday:2]; // Sunday == 1, Saturday == 7
NSUInteger adjustedWeekdayOrdinal = [gregorian ordinalityOfUnit:NSWeekdayCalendarUnit inUnit:NSWeekCalendarUnit forDate:[NSDate date]];
NSLog(#"Adjusted weekday ordinal: %d", adjustedWeekdayOrdinal);
Remember, the ordinals for weekdays start at 1 for the first day of the week, not zero.
Documentation link.
This code constructs a date that is set to Monday of the current week:
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDate *beginningOfWeek = nil;
BOOL ok = [gregorian rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek
interval:NULL forDate: today];
setFirstWeekday: on the NSCalendar object.
Sets the index of the first weekday for the receiver.
- (void)setFirstWeekday:(NSUInteger)weekday
Should do the trick.
In my opinion this settings should be dynamic according to the user locale.
Therefore one should use:
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setLocale:[NSLocale currentLocale]];
This will cause the calendar to set the first week day according to the user locale automatically. Unless you are developing your app for a specific purpose/user locale (or prefer to allow the user to choose this day).
I've done it like this.
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDateComponents *compForWeekday = [gregorian components:(NSWeekdayCalendarUnit) fromDate:today];
NSInteger weekDayAsNumber = [compForWeekday weekday]; // The week day as number but with sunday starting as 1
weekDayAsNumber = ((weekDayAsNumber + 5) % 7) + 1; // Transforming so that monday = 1 and sunday = 7
I had trouble with a lot of the answers here. . maybe it was just me. .
Here's an answer that works for me:
- (NSDate*)firstDayOfWeek
{
NSCalendar* cal = [[NSCalendar currentCalendar] copy];
[cal setFirstWeekday:2]; //Override locale to make week start on Monday
NSDate* startOfTheWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
return startOfTheWeek;
}
- (NSDate*)lastDayOfWeek
{
NSCalendar* cal = [[NSCalendar currentCalendar] copy];
[cal setFirstWeekday:2]; //Override locale to make week start on Monday
NSDate* startOfTheWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
return [startOfTheWeek dateByAddingTimeInterval:interval - 1];
}
Update:
As pointed out (elsewhere) by #vikingosegundo, in general its best to let the local determine which day is the start of the week, however in this case the OP was asking for the start of the week to occur on Monday, hence we copy the system calendar, and override the firstWeekDay.
The problem with Kris' answer is the edge case where the beginning of the week starts in the prior month. Here's some easier code and it also checks the edge case:
// Finds the date for the first day of the week
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
NSCalendar *calendar = [NSCalendar currentCalendar];
// Edge case where beginning of week starts in the prior month
NSDateComponents *edgeCase = [[NSDateComponents alloc] init];
[edgeCase setMonth:2];
[edgeCase setDay:1];
[edgeCase setYear:2013];
NSDate *edgeCaseDate = [calendar dateFromComponents:edgeCase];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:edgeCaseDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Edge case date is %# and beginning of that week is %#", edgeCaseDate , [calendar dateFromComponents:components]);
// Find Sunday for the given date
components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Original date is %# and beginning of week is %#", givenDate , [calendar dateFromComponents:components]);
return [calendar dateFromComponents:components];
}
I see misunderstanding in the other messages. The first weekday, whichever it is, has number 1 not 0. By default Sunday=1 as in the "Introduction to Date and Time Programming Guide for Cocoa: Calendrical Calculations":
"The weekday value for Sunday in the Gregorian calendar is 1"
For the Monday as a first workday the only remedy I have is brute force condition to fix the calculation
NSCalendar *cal=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [cal components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
// set to 7 if it's Sunday otherwise decrease weekday number
NSInteger weekday=[comps weekday]==1?7:[comps weekday]-1;
Below also covers the edge case,
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:2]; // 1 == Sunday, 7 == Saturday
if([[calendar dateFromComponents:components] compare: curDate] == NSOrderedDescending) // if start is later in time than end
{
[components setWeek:[components week]-1];
}
return [calendar dateFromComponents:components];
}
You can just change .firstWeekday of the calendar.
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
calendar.firstWeekday = 2;
Then use rangeOfUnit:startDate:interval:forDate: to get the first day
NSDate *startOfWeek;
[calendar rangeOfUnit:NSCalendarUnitWeekOfYear startDate:&startOfWeek interval:nil forDate:[NSdate date]];
Try this:
NSCalendar *yourCal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]
[yourCal setFirstWeekday:0];
Iv found out the way to display any weekday name using nscalender..using the following code..
Just open your console from xcode menu bar to see the results.Copy Paste the following code in your viewDidLoad method to get the first day of the week
NSDate *today = [NSDate date];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"MM/dd/yyyy :EEEE"];
NSString *dateString = [dateFormat stringFromDate:today];
NSLog(#"date: %#", dateString);
[dateFormat release];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
[components setDay:([components day]-([components weekday]-1))];
NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:#"MM/dd/yyyy :EEEE"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek];
NSLog(#"First_date: %#", dateString_first);
The Output will be:
date: 02/11/2010 :Thursday
First_date: 02/07/2010 :Sunday
since i had run this program on 2/11/2010 u will get the desired output depending on the current date.
Similarly if u want to get the first working day of the week i.e Monday's date then just modify the code a bit:
CHANGE :[components setDay:([components day]-([components weekday]-1))];
TO
[components setDay:([components day]-([components weekday]-2))];
to get Mondays date for that week..
Similarly u can try to find the date of any of seven workdays by changing the integer -1,-2 and so on...
Hope u r question is answered..
Thanks,
Bonson Dias
The ISO 8601 calendar appears to have it's first weekday set to monday by default.
Using the Calendar nextWeekend (iOS 10 or later) and ordinality (thanks #kris-markel). I've gotten Monday as first of the week for the en_US calendar.
Here is an example of it with fallback to firstWeekday:
extension Calendar {
var firstWorkWeekday: Int {
guard #available(iOS 10.0, *) else{
return self.firstWeekday
}
guard let endOfWeekend = self.nextWeekend(startingAfter: Date())?.end else {
return self.firstWeekday
}
return self.ordinality(of: .weekday, in: .weekOfYear, for: endOfWeekend) ?? self.firstWeekday
}
}
The Swift solution (note, use .yearForWeekOfYear, not .year):
let now = Date()
let cal = Calendar.current
var weekComponents = cal.dateComponents([.yearForWeekOfYear, .weekOfYear,
.weekday], from: now)
//weekComponents.weekday = 1 // if your week starts on Sunday
weekComponents.weekday = 2 // if your week starts on Monday
cal.date(from: weekComponents) // returns date with first day of the week
… is there a calendar that already has Monday as the first day of the week, instead of Sunday.
Someday, there will be.
My simple way of doing this is to get Monday = 0, Sunday = 6:
NSDateComponents *dateComponents = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
NSInteger dayNumStartingFromMonday = ([dateComponents weekday] - 2 + 7) % 7; //normal: Sunday is 1, Monday is 2